1. Field of the Invention
The invention relates in general to a sensor, and more particularly to a sensing apparatus and a scan driving method thereof.
2. Description of the Related Art
In recent years, touch-control function has been widely used in life. For example, the dynamic gray pressure sensor is used for home care identification, capacitive pressure sensor, directivity touch-control of panel, multi-touch and so on. Therefore, large area sensor scanning, array, three-dimensional sensing and multi-touch sensing technology will be the future trend of consumer electronics. However, it causes the sensing circuit relatively complicated. So it is a hot topic to greatly simplify architecture of scanning actuation and sensing circuit.
A dynamic response scan circuit of an array-type pressure sensing element is disclosed in FIG. 1 of U.S. Pat. No. 5,505,072. The scan circuit sequentially scan-drives column electrodes according to a current feedback signal VTEST. The signal VTEST flows through a piezoresistive sensor and voltage signals are acquired through a negative feedback amplifier. Finally, an analog-to-digital converter sequentially reads the voltage signals to build the position of the array sensing element.
An output circuit of a pressure sensing element is disclosed in FIG. 3 of U.S. Pat. No. 5,905,209. The output circuit acquires voltage signals of sensing elements by sequentially switching column electrodes according to a grounding signal GND, and then using the voltage sensing architecture of row electrodes.